On Aquatic Carnivorous Coleoptera or Dytiscidce. 633 



I. 65.— Genus HYDERODES. 



Yellow colour of clypeus not sharply limited from the dark colour of the front of 

 the head ; and this dark colour in the middle extends distinctly on to the clypeus. 



Clypeal suture obliterated in the middle. Elytra unicolorous, destitute of yellow 

 border. 



This genus comprises only three species, peculiar to Australia and Tasmania. 



980. riyderodes shuckardi, Hope, M.C — Ovalis, robustus, convexus, nigricans, 

 superne (prgesertim in thorace), nitidus, subviridescens, clypeo et prothoracis 

 lateribus testaceis, antennis rufis, pedibas piceis ; prothorace lateribus crasse margi- 

 nalis, intra marginsm parum impresso ; elytris punctis seriatis conspicuis, punctis- 

 que sparsis minutis versus latera et apicem minus subtilibus. Long. 1 9, lat. 11 m.m. 



Var. feminae, thorace elj^trisque opacis, rugosis, quasi profunde erosis. 



The male lias the three basal joints of the front tarsi very broadly dilated, and 

 coadapted to form a circular plate, which is furnished beneath with large and 

 distinctly stalked palettes rather variable in size, the marginal ones being smaller, 

 but the four near the base larger than the rest ; the fourth joint is quite simple 

 and rather short, the fifth rather long, about equal to the length of the three 

 dilated basal joints, the claws are moderately long and a little unequal, the anterior 

 one being more curved than the other. The intermediate tarsi have the three basal 

 joints much dilated, so as to form an oblong oval plate, which is furnished beneath 

 with palettes similar to those of the front feet, but differing less inter se as to size, 

 and leaving a bare glabrous space at the base of the tarsus ; on the hind feet four 

 joints of the tarsus are furnished beneath rather scantily with fine hairs. The 

 female is a little smaller than the male and shows a slight difference in the form of 

 the thorax : the second form of this sex with deeply corroded upper surface is very 

 remarkable. 



According to the specimens before me the species varies a good deal in breadtli, 

 and somewhat in colour, the greenish-black tinge of the uppersur face giving place 

 sometimes to a piceous tint ; the length and breadth of the prosternal process also 

 exhibit a good deal of variation. 



Tasmania, South Australia, New Soutli Wales. 932. 



981. Hyderodes crassus, n. sp. — Ovalis, latus, robustus, convexus, nigricans, 

 nitidus, superne subviridescens, clypeo et prothoracis lateribus testaceis, antennis 

 rufis, pedibus piceis ; prothorace lateribus baud crasse marginatis, sed intra mar- 

 ginem conspicue depresso ; elytris punctis seriatis conspicuis, punctisque sparsis 

 versus latera et apicem minus subtilibus. Long. 19, lat. II2 m.m. 



